In Radio Frequency (RF) communication systems, Multiple-Input, Multiple-Output (MIMO) has been an important enabling technology for high-rate wireless standards in communications. Compared with conventional Single-Input, Single-Output (SISO) links, a MIMO transmitter can code the same data symbols through multiple antennas, thus achieving a diversity gain. A MIMO transmitter can also allow parallel transmission of different data symbols through different antennas, thus achieving a multiplexing gain.
Both diversity and multiplexing mechanisms typically scale throughput with the number of antennas without requiring additional RF spectrum. However, a MIMO radio must accompany each antenna with a separate RF chain, including, for example, a Digital to Analog Converter (DAC), amplifier, various filters and the like. Such components in an RF chain account for a significant amount of an RF transceiver's power cost, and MIMO power consumption typically increases linearly with the number of RF chains. As a result, the addition of RF chains and antennas often nullifies the improvement in link capacity, which may result in even lower energy-per-bit than SISO. What is needed is an improved mechanism for RF communication in which data may be communicated more efficiently (with link capacity increased) without increasing power limitations.